In general, inkjet printers include at least one printhead that ejects drops of liquid ink directly onto recording media or onto a surface of an intermediate image receiving member for transfer to recording media. The intermediate image receiving member in an indirect inkjet printer can be a rotating metal drum or endless belt. In a direct printer, the recording media can be in sheet or continuous web form. A phase change inkjet printer employs phase change inks that are solid at ambient temperature, but transition to a liquid phase at an elevated temperature. Once the melted ink is ejected onto recording media or the surface of an intermediate image receiving member, the ink droplets quickly solidify to form an ink image.
Printers typically conduct various maintenance operations to ensure proper operation of the inkjets in each printhead. One known maintenance operation removes particles or other contaminants that may interfere with printing operations from each printhead in a printer. During such a cleaning maintenance operation, the printheads purge ink through some or all of the inkjets in the printhead. The purged ink flows from the apertures of the inkjets that are located in a faceplate of each printhead onto the faceplate.
In printheads that are oriented vertically or at least partially vertically, the purged ink rolls downwardly under the effect of gravity to an ink drip bib mounted at the lower edge of the faceplate or onto a flexure chute mounted on a maintenance station. The drip bib or flexure chute is configured to collect the liquid ink and direct the ink into an ink receptacle.
In some printers, including those mounted horizontally, one or more wipers are manipulated to contact the faceplate of each printhead and wipe the purged ink toward the drip bib to facilitate the collection and removal of the purged ink. However, when a large quantity of ink is present on the printhead face, such as after a purging operation, the wiper can sometimes smear the ink across the face of the printhead, leaving a layer of ink on the faceplate after the wiping is complete.
Additionally, when preparing a printhead for a period of non-use, some printheads are flushed with a cleaning fluid to loosen and/or remove solvents, resins, and other compounds from the inkjet nozzles. However, it is often difficult to remove all of the flushing fluid mixed with the solvents, resins, and other compounds. Wiping a printhead having these solvents, resins, and other compounds on the face can force these compounds into the inkjet nozzles, clogging and contaminating the nozzles.
Furthermore, in printheads configured to eject more than one color of ink, wiping the printhead mixes the ink on the printhead and forces some of the mixed ink into the inkjet nozzles. The mixed ink in the inkjet nozzles reduces print quality in subsequent printing operations or requires jetting of additional ink before commencing a printing operation to clear the nozzles, which results in wasted ink. Thus, improved cleaning of printheads is desirable.